Currently there are shipping freezers on the market that keep the customer's products at a low temperature. However, these prior art shipping freezers have severe limitations, such as lack of temperature control, the need for continual external power, flammable fuels, limited shipping durations, etc.
One prior art method of cooling is through the use of blocks of solid Carbon Dioxide, which sublimates at −78 deg. C. Another method of cooling is by pouring liquid Nitrogen, which liquefies at −196 deg C., into the payload bay and surrounding the customer's product.
In both cases, there is the drawback that the customer's product will be cooled to near the temperature of the energy source: −78 deg. C. for Carbon Dioxide, and −196 deg. C. for liquid Nitrogen. Those temperatures are not controllable and may be detrimental to the product.
Yet another method of cooling is with a mechanical means that requires large amounts of electricity to power the compressors. These units usually require an outside power source during shipping. Many times this power is not available or is of limited amounts. Further, some mechanical freezers have a large Diesel generator. Drawbacks of conventional solutions may include one or more of the following: 1. Large volume of Diesel fuel required. 2. Danger of a toxic and flammable fuel. 3. Danger of harmful emissions from the exhaust gas. 4. Reliability concerns of continual operation of the Diesel engine and the plurality of wearing parts.